Repeating that sex is a spectrum won't convince anyone, especially when you can't even explain how babies are made.

Sex is about reproduction. We're an anisogamic species, which means we reproduce through the production of specialized cells with half the DNA (gametes) of different size. Male individuals are the ones who produce small gametes (spermatozoon) and females are the ones who produce large gametes (ovum). Then, a spermatozoon and an ovum fuse to form the zygote, restoring this way the normal amount of DNA. Some species are hermaphrodites, which means they can produce both male and female gametes. Humans are not hermaphrodites, though. There are several genes involved in the process of sex determination, but one of the most important is the SRY gen, which is located in the Y chromosome. If this gen is present, then the embryo will develop testes. If not, then it’ll will develop ovaries. The hormones secreted by the testes drive the male differentiation pathway for the rest of the male reproductive organs. And the absence of these hormones drives the female differentiation pathway.

There are some people who have a disorder of sexual development (DSD), but they are rare and they are still either male or female, i.e. they don't produce a third type of gamete.

Also, in mammals, females give birth to the offspring (the only exception being monotremes, who lay eggs). Female mammals also nourish the young with milk produced by their mammary glands.

BTW, I think QT should be the last to say "feelings aren't facts".